EP0102573B1 - Polycarbonates containing end groups with conjugated double bonds which may be mixed with known aromatic polycarbonates, process for their preparation and their uses - Google Patents

Description

The present invention relates to a process for the preparation of aromatic polycarbonates with end groups containing conjugated double bonds and with average molecular weights Mw (weight average, determined by light scattering) between 5000 and 100,000, optionally in a mixture with known aromatic polycarbonates with Mw between 5,000 and 100,000 , from diphenols, phosgene, 1 to 20 mol%, based on moles of diphenols, chain terminators and optionally branching agents according to the known polycarbonate production methods of the phase boundary process or the process in homogeneous solution, which is characterized in that chain terminators of the formula (I)

XA- (CH ₂ ) _n -CH = CH-CH = CH-R (I)

optionally used in combination with maximum equal molar amounts of other known chain terminators.

In the chain terminators of formula (I) R is an aromatic radical having 6 to 20 carbon atoms, especially phenyl, or a C, -C _a alkyl, which linear or branched kan, especially methyl. The variable 'n' is 'o' or an integer between 1 and 7.

oder ein Rest

und X- eine funktionelleIn the chain terminators of the formula (I), XA-either X-, that is -A-, is a single bond or a radical

or a rest

and X- a functional one

Group which functions as a reactive part of the chain terminators of the formula (I) in the polycarbonate production by the two-phase interface process or by the homogeneous phase process (pyridine process).

oder HO-Z-O-K- sein.For example

or HO-ZOK-.

oder

• R, ist ein aromatischer Rest mit vorzugsweise 8 bis 20 C-Atomen, insbesondere Phenyl, oder ein aliphatischer Rest mit 1 bis 8 C-Atomen, insbesondere Methyl; -O-Z-Oist ein Diphenolatrest mit vorzugsweise 6 bis 30 C-Atomen;
  

X- is preferably

or

• R is an aromatic radical with preferably 8 to 20 C atoms, in particular phenyl, or an aliphatic radical with 1 to 8 C atoms, in particular methyl; -OZ-O is a diphenolate residue with preferably 6 to 30 C atoms;
  

Known other chain terminators to be used in the process according to the invention are, for example, phenols, carboxylic acid halides, sulfonic acid chlorides or chlorocarbonic acid esters.

Examples of the known chain terminators to be used are phenol, p-tert-butylphenol, 2,6-dimethylphenol or p-isooctylphenol.

monosorbinsäureester oder 2, 2-Bis- (4-hydroxyphenyl) -propan-monosorb insäureester.Examples of the chain terminators of the formula (I) are sorbic acid chloride, sorbic acid, sorbic alcohol (CH ₃ -CH = CH-CH = CH-CH20H), the chlorocarbonic acid ester of sorbic alcohol,

monosorbic acid ester or 2,2-bis (4-hydroxyphenyl) propane monosorbic acid ester.

The diphenol monoesters, such as hydroquinone monosorbic acid esters or 2,2-bis (4-hydroxyphenyl) propane monosorbic acid esters, can be prepared, for example, by mixing the corresponding diphenol and sorbic acid chloride in a molar ratio of 1: 1 to 5: 1 in an organic solvent with a boiling point of dissolves at least 80 ⁰ C, the solution is heated to at least 80 ° C and the resulting HCl expels in a stream of nitrogen.

worin R, 'n" und -A- die für die Formel (I) genannte Bedeutung haben, gegebenenfalls im Gemisch mit bekannten aromatischen Polycarbonaten, mit Mw zwischen 5 000 und 100 000, die aus dem Kettenabbruch mit den anderen, bekannten Kettenabbrechern resultieren.The present invention also relates to the aromatic polycarbonates with conjugated double bonds and end groups of the formula (Ia) obtainable by the process according to the invention.

wherein R, 'n "and -A- have the meaning given for the formula (I), optionally in a mixture with known aromatic polycarbonates, with Mw between 5,000 and 100,000, which result from chain termination with the other known chain terminators.

worin -0-Z-0- ein Diphenolatrest mit vorzugsweise 6 bis 30 C-Atomen ist,Aromatic polycarbonates obtainable by the process according to the invention with average molecular weights M w (weight average determined by light scattering) between 5000 and 100 000 are preferably those of the formula (I)

in which -0-Z-0- is a diphenolate radical preferably having 6 to 30 C atoms,

E and E 'are identical or different and at least one of the radicals E or E' corresponds to a radical of the formula (Ib) -YA- (CH ₂ ) _n -CH = CH CH = CH-R, where R, 'n " and -A- have the meaning given for formula (I) and -Y is the link that results from the reaction of the chain terminators of formula (I), optionally with the inclusion of phosgene, and wherein the other end groups E and E 'from the reaction with the other known chain terminators, optionally with the inclusion of phosgene, and where 'p' is the degree of polymerization which results from the molecular weights Mw of 5,000 to 100,000.

oder

wobei R₁, Z und K die oben für die X-Reste genannte Bedeutung hat.Examples of the links -Y- are

or

where R ₁ , Z and K has the meaning given above for the X radicals.

und

Examples of preferred links -Y- are

and

Because of the end groups, the polycarbonates according to the invention have the ability to increase their molecular weight on prolonged heating, that is to say on heat treatment.

Thermoplastic, aromatic polycarbonates with unsaturated end groups are known (see German Offenlegungsschriften No. 2 746 139 (Le A 18 392), 2 829 256 (Le A 18 847), 2 843 154 (Le A 19 147) and 2 842 004 (Le A 19 148)). The double bonds of these polycarbonates can

can be used for certain reactions (grafting, UV light crosslinking).

A targeted molecular weight build-up during heating does not occur with these polycarbonates, rather these products are still stable at temperatures from 280 ° C to 300 ° C.

Diphenols of the formula (III) HO-Z-OH (III) with preferably 6 to 30 carbon atoms which are suitable for the preparation of the polycarbonates according to the invention are both mononuclear and multinuclear diphenols which can contain heteroatoms and under the conditions of polycarbonate production and their thermal treatment may have inert substituents.

Examples include hydroquinone, resorcinol, dihydroxydiphenyl, bis - (hydroxyphenyl) alkanes, bis (hydroxyphenyl) cycloalkanes, bis (hydroxyphenyl) sulfides, ethers, ketones, sulfoxides, sulfones and a, a-bis (Hydroxy-phenyl) - diisopropylbenzenes and their nuclear alkylated and nuclear halogenated compounds.

Suitable diphenols are described, for example, in U.S. Patents 3,028,365, 2,999,835, 3,062,781 and 3,148,172, in German Offenlegungsschriften 1,570,703 and 2,063,050 and in the monograph 'H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York; 1964 ".

• 4,4' -Dihydroxydiphenyl
• 2,2-Bis - (4 -hydroxyphenyl) -propan
• 2,4 -Bis- (4-hydroxyphenyl) -2-methylbutan
• 1,1 -Bis - (4-hydroxyphenyl) -cyclohexan
• a,a-Bis - (4 -hydroxyphenyl) -p-diisopropylben zol
• 2,2-Bis - (3-methyl-4 -hydroxyphenyl) -propan
• 2,2-Bis- (3-chlor-4-hydroxyphenyl) -propan
• Bis- (3, 5-dimethyl-4-hydroxyphenyl) -methan
• 2, 2-Bis- (3, 5-dimethyl-4-hydroxyphenyl) - propan
• Bis- (3, 5-dimethyl-4-hydroxyphenyl) -sulfon
• 2,4 -Bis- (3, 5-dimethyl-4-hydroxyphenyl) -2-methylbutan
• 1,1 -Bis - (3, 5-dimethyl -4 -hydroxyphenyl) - cyclohexan
• a,a'-Bis- (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropylbenzol
• 2,2-Bis- (3,5-dichlor-4-hydroxyphenyl) -propan
• 2,2-Bis- (3, 5-dibrom-4-hydroxyphenyl) -propan. Besonders bevorzugte Diphenole sind z.B:
• 2,2-Bis- (4 -hydroxyphenyl) -propan
• 2,2-Bis- (3, 5-dimethyl-4-hydroxyphenyl) - propan
• 2,2-Bis- (3, 5-dichlor-4-hydroxyphenyl) -propan
• 2,2-Bis- (3, 5-dibrom-4-hydroxyphenyl) -propan
• 1,1 -Bis - (4 -hydroxyphenyl) -cyclohexan.

Preferred diphenols are

• 4,4'-dihydroxydiphenyl
• 2,2-bis - (4-hydroxyphenyl) propane
• 2,4-bis (4-hydroxyphenyl) -2-methylbutane
• 1,1-bis - (4-hydroxyphenyl) cyclohexane
• a, a-bis - (4-hydroxyphenyl) -p-diisopropylbenzene
• 2,2-bis - (3-methyl-4-hydroxyphenyl) propane
• 2,2-bis (3-chloro-4-hydroxyphenyl) propane
• Bis (3,5-dimethyl-4-hydroxyphenyl) methane
• 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane
• Bis (3,5-dimethyl-4-hydroxyphenyl) sulfone
• 2,4-bis (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane
• 1,1-bis - (3,5-dimethyl -4-hydroxyphenyl) cyclohexane
• a, a'-bis (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropylbenzene
• 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane
• 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane. Particularly preferred diphenols are, for example:
• 2,2-bis (4-hydroxyphenyl) propane
• 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane
• 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane
• 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane
• 1,1-bis - (4-hydroxyphenyl) cyclohexane.

Any mixtures of the aforementioned diphenols can also be used.

In addition to the monomeric diphenols mentioned, oligomers or can also be used to prepare block copolycarbonates with the end groups according to the invention Polymers are also used which carry two end groups which are concerned with the building-up reaction under the conditions of polycarbonate synthesis. Such end groups are, for example, phenolic OH groups, chlorocarbonic acid ester groups and carboxylic acid chloride groups. Prefabricated oligomeric or polymeric blocks which already carry the reactive groups mentioned as a result of the nature of their preparation or in which such groups can be produced by suitable aftertreatment are, for example, polysiloxanes, polycondensates based on aliphatic diols and saturated aliphatic or aromatic dicarboxylic acids, aromatic Polyethers, aromatic polyether sulfones, aliphatic polyethers and saturated aliphatic polyesters based on dimer fatty acid.

Such co-condensable, bifunctional oligomers or polymers can have molecular weights Mn (number average determined by vapor pressure osmosis) between 50 and 5000 and are used in such amounts that the resulting polycarbonates containing unsaturated end groups according to the invention contain between 0 and 80% by weight.

The present invention thus also relates to the modification of the production process according to the invention, which is characterized in that bifunctional oligomers or polymers with molecular weights Mn (number average) between 500 and 5000 in amounts of 0 to 450% by weight which are co-condensable under the polycarbonate production conditions to the amount by weight of monomeric diphenols used.

The present invention thus also relates to the aromatic segmented polycarbonates obtainable by this modified process according to the invention with end groups of the formula (Ia) containing conjugated double bonds, optionally in a mixture with known aromatic segmented polycarbonates which result from chain termination with the other known chain terminators .

In order to improve the flow behavior, small amounts, preferably amounts between 0.05 and 2.0 mol% (based on moles of diphenols used), of tri- or more than trifunctional compounds, in particular those with three or more than three phenolic compounds, can also be used Hydroxyl groups can be used in a known manner. Some of the usable compounds with three or more than three phenolic hydroxyl groups are, for example, 1.3. 5-tri- (4-hydroxyphenyl) benzene, 1.1.1-tri- (4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5'-methylbenzyl) -4-methylphenol, 2- (4-Hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane, hexa- (4- (4-hydroxyphenylisopropyl) phenyl) ortho-terephthalic acid ester, tetra- (4-hydroxyphenyl) methane and 1.4 -Bis- ((4'.4 "- dihydroxytriphenyl) methyl) - benzene. Some of the other three-functional compounds are 2. 4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and 3,3-bis- (4-hydroxy-3-methylphenyl ) -2-oxo-2,3-dihydro indole.

• 1. Nach dem Lösungsverfahren ih disperser Phase (sogenanntes ZweiphasengrenzflächenVerfahren):
  • Hierbei werden die einzusetztenden Diphenole in wäßriger alkalischer Phase gelöst. Dazu werden die zur Herstellung der erfindungsgemäßen Polycarbonate erforderlichen Kettenabbrecher in Mengen von 1,0-20,0 Moi-0/o, bezogen auf Mole Diphenol, in einem organischen Lösungsmittel gelöst oder in Substanz, zugegeben. Dann wird in Gegenwart einer inerten, vorzugsweise Polycarbonatlösenden, organischen Phase mit Phosgen umgesetzt. Die Reaktionstemperatur liegt zwischen 0 ° C bis 40°C.

The polycarbonates or polycarbonate mixtures according to the invention can essentially be prepared by the following two known methods (cf. H. Schnell, 'Chemistry and Physics of Polycarbonates', Polymer Reviews, Vol. IX, page 27 ff., Interscience Publ. 1964):

• 1. According to the disperse phase solution process (so-called two-phase interface process):
  • The diphenols to be used are dissolved in an aqueous alkaline phase. For this purpose, the chain terminators required for the preparation of the polycarbonates according to the invention are added in amounts of 1.0-20.0 mol / o, based on moles of diphenol, dissolved in an organic solvent or in bulk. The reaction is then carried out with phosgene in the presence of an inert, preferably polycarbonate-dissolving, organic phase. The reaction temperature is between 0 ° C to 40 ° C.

The type and amount of the chain terminators required, as stated above, can also be added during phosgenation.

Suitable organic solvents for the chain terminators are, for example, methylene chloride, chlorobenzene, mixtures of methylene chloride and chlorobenzene, acetone, acetonitrile, toluene.

The reaction can be promoted by catalysts such as tributylamine or triethylam. In order to favor the incorporation of the chain terminator, onium salts, such as tetraalkylammonium halides, can also be used as phase transfer catalysts.

If branching agents or co-condensable bifunctional oligomers or polymers are also used, they can be added before the reaction with phosgene or during the phosgenation.

In addition to or instead of the diphenols, their chlorocarbonic acid esters can also be used.

• Hierbei werden die Diphenole ih organischen Basen wie Pyridin gelöst, gegebenenfalls unter Zusatz weiterer organischer Lösungsmittel; dann werden, wie unter 1. beschrieben, die zur Herstellung der erfin-dungsgemäßen Polycarbonate erforderlichen Kettenabbrecher in Mengen von 1, 0 - 20,0 Mol-%, bezogen auf Mol Diphenol, bei Raumtemperatur zugegeben.

2. After the solution process in a homogeneous phase (also called pyridine process):

• Here, the diphenols are dissolved in organic bases such as pyridine, optionally with the addition of further organic solvents; then, as described under 1., the chain terminators required for the preparation of the polycarbonates according to the invention are added in amounts of 1.0-20.0 mol%, based on mol of diphenol, at room temperature.

Then it is reacted with phosgene. The reaction temperature is between 0 ° C and 40 ° C. Suitable organic bases apart from pyridine are, for example, triethylamine, tributylamine; suitable Solvents are, for example, methylene chloride, chlorobenzene, toluene or mixtures of methylene chloride and chlorobenzene or toluene.

The process variants 1 and 2 isolate the polycarbonates according to the invention in a known manner. In order not to bring about a partial build-up of the molecular weight during processing, temperatures above 100 ° C. should not be used if possible. Suitable work-up methods are, in particular, the precipitation, the spray drying and the evaporation of the solvent in a vacuum.

If branching agents or co-condensable bifunctional oligomers are also used, the procedure described under 1 is followed.

In addition to the diphenols, up to 50 mol%, based on the diphenols used, of their bischlorocarbonic acid esters can also be used.

The polycarbonates according to the invention can be converted into polycarbonates with a higher molecular weight by heating to temperatures between 150 ° C. to 400 ° C., preferably to temperatures between 200 ° C. to 350 ° C. Branched polycarbonates can result in crosslinked, insoluble products. The duration of the heat treatment depends on the set maximum temperature and the desired molecular weight build-up. The heat treatment is advantageously carried out during processing into moldings in extruders, presses or injection molding machines. It can also be done by melting in kneaders or stirred tanks. The extent of the molecular weight increase is e.g. by comparing the solution viscosity of the sample before and after the heat treatment.

The polycarbonates according to the invention offer the advantage that molded articles made of very high molecular weight polycarbonate can be produced from low-viscosity, easy-flowing polycarbonates. Such moldings generally have better mechanical and chemical properties than those made from low molecular weight material.

Before or during their processing, the polycarbonates according to the invention can also be mixed with known aromatic thermoplastic polycarbonates with Mw (weight average molecular weight, measured by the light scattering method) of 10,000 to 200,000, in amounts of 5 to 95% by weight, based on the The amount by weight of polycarbonates having end groups containing conjugated double bonds according to the invention are mixed.

Such mixtures can also be obtained in part by selecting the molar ratio of chain terminator of the formula (I) according to the invention to known chain terminator between 0.05 and 0.90 in the preparation according to the invention of the polycarbonates having end groups containing conjugated double bonds.

The present invention thus also relates to mixtures consisting of 5 to 95% by weight of polycarbonate of the formula II and 95 to 5% by weight of known, aromatic, thermoplastic polycarbonates with Mw (weight average molecular weight) of 10,000 to 200,000.

In the following examples, η rel. measured in CH ₂ C1 ₂ at 25 ° C and a concentration of 0.5 g per 100 ml CH ₂ CI ₂ .

example 1

A solution is prepared from 1.571 kg of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) (6.88 mol), 1.223 kg of a 45% aqueous sodium hydroxide solution and 1 1 1 of distilled water. After adding 27 liters of methylene chloride, a solution consisting of 2 1 methylene chloride, 62.6 kg of sorbic acid chloride (0.48 mol), 396 g of bisphenol A-bischlorocarbonic acid ester (1.1 2 mol) and 25.8 g of tetrabutylammonium bromide (0.08 mol) were run in. Subsequently, 1.105 kg (1 1.68 mol) phosgene are introduced at 20 ° C.-25 ° C. with stirring. The pH is maintained at pH 12 during the phosgenation by adding a further 2.29 kg of 45% strength aqueous sodium hydroxide solution. After the introduction of phosgene has ended, the pH is raised to pH 13 by the addition of a further 0.07 kg of 45% strength aqueous sodium hydroxide solution, 7 g of triethylamine are added and the mixture is stirred for a further 30 minutes. The upper aqueous phase is separated off, the organic phase is acidified and washed free of electrolytes. The methylene chloride solution is concentrated, the product obtained is crushed and dried in a vacuum drying cabinet at 80 ° C. for 24 h. The relative solution viscosity is 1,159.

In each case 2 g of the polycarbonate obtained are dissolved in 20 ml of methylene chloride, the solutions are each placed in a 100 ml round-bottomed flask and the solvent is removed at 30-40 ° C. in a water jet vacuum on a rotavapor.

• η rel (Ausgangsprobe) = 1, 1 59
• Temperung: 5 Min. bei 270 °C η rel (nach Temperung)
• = 1,169
• 5 Min. bei 290°C η rel (nach
• Temperung)
• = 1,190
• 5 Min. bei 310°C η rel (nach
• Temperung)
• = 1,205.

In this way, polycarbonate films are obtained on the inside of the flask. The flasks are then immersed in salt baths at different temperatures for 5 minutes each and the molecular weight build-up at the temperatures used is determined in this way:

• η rel (initial sample) = 1, 59
• Annealing: 5 min. At 270 ° C η rel (after annealing)
• = 1.169
• 5 min. At 290 ° C η rel (after
• Tempering)
• = 1.190
• 5 min. At 310 ° C η rel (after
• Tempering)
• = 1.205.

Example 2

A solution is prepared from 2.192 kg of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) (9.6 mol), 1.787 kg of a 45% aqueous sodium hydroxide solution and 14 l of distilled water. After adding 34 l of methylene chloride, 1.580 kg of phosgene (16 mol) are introduced at 20-25 ° C., and after 5 minutes from the start of phosgene introduction, a solution consisting of 32.2 g (0.1 mol) of tetrabutylammonium bromide, 141 2 g (0.4 mol) bisphenol-A-bischlorocarbonate, 52.5 g (0.4 mol) of sorbic acid chloride and 2 l of methylene chloride were added dropwise in parallel with the introduction of phosgene, so that the solution was added dropwise 5 to 10 minutes before the introduction of phosgene had ended. The pH is maintained at pH 12-13 during the phosgenation by adding 2.365 kg of 45% aqueous sodium hydroxide solution.

After the phosgenation has ended, 275 ml of 4% N-ethylpiperidine solution are added and the mixture is stirred for a further 45 minutes. The upper aqueous phase is separated off, the organic phase is acidified and washed free of electrolytes. The polycarbonate was precipitated from the organic phase in twice the amount of acetone and dried for 12 hours at 130 ° C. in a vacuum drying cabinet. The real solution viscosity is 1.256.

Transparent films were pressed from the material obtained. The conditions during the pressing and the solution viscosity measured on the films after the pressing is shown in Table 1 below.

Example 3

A solution is prepared from 45.7 g of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) (0.2 mol), 16 g of sodium hydroxide (0 4 mol) and 680 ml of distilled water. After adding 2.36 g of p-hydroxithiophenylsorbic acid ester (0.01 mol) dissolved in 370 ml of methylene chloride, 32 g (0.32 mol) of phosgene are introduced at 20 ° C.-25 ° C. with stirring. The pH is maintained at pH 12 during the phosgenation by adding 20 ml of 45% aqueous sodium hydroxide solution. After phosgenation has ended, the pH is raised to pH 13-14 by adding a further 20 ml of 45% aqueous sodium hydroxide solution, 4 ml of 4% aqueous triethylamine solution is added and the mixture is stirred for a further 45 minutes. The upper aqueous phase is separated off, the organic phase is acidified and washed free of electrolytes.

The methylene chloride solution is concentrated and the product is dried at 80 ° C. for 12 hours in a vacuum drying cabinet.

The relative solution viscosity is 1,247.

In each case 2 g of the polycarbonate obtained are dissolved in 20 ml of methylene chloride, the solutions are each placed in a 100 ml round-bottomed flask and the solvent is removed at 30-40 ° C. in a water jet vacuum on a rotary evaporator.

• η rel (Ausgangsprobe) = 1,247
• Temperung: 5 -Minuten bei 290 °C η rel (nach
• Temperung) = 1,360
• 5 Minuten bei 300 °C η rel (nach
• Temperung) = 1,320
• 5 Minuten bei 310 °C η rel (nach
• Temperung) = 1,346
• 10 Minuten bei 290°C η rel (nach
• Temperung) = 1,367
• 15 Minuten bei 290°C η rel (nach
• Temperung) = 1,363.

In this way, polycarbonate films are obtained on the inside of the flask. The flasks are then immersed in salt baths at different temperatures for a certain period of time and the molecular weight build-up at the temperatures used is determined in this way.

• η rel (initial sample) = 1.247
• Annealing: 5 minutes at 290 ° C η rel (after
• Annealing) = 1.360
• 5 minutes at 300 ° C η rel (after
• Annealing) = 1.320
• 5 minutes at 310 ° C η rel (after
• Annealing) = 1.346
• 10 minutes at 290 ° C η rel (after
• Annealing) = 1,367
• 15 minutes at 290 ° C η rel (after
• Annealing) = 1,363.

Example 4

Preparation of a chain terminator: 22.8 g of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) (0.1 mol) and 13.0 g of sorbic acid chloride (0.1 mol) are added to 250 ml of dry toluene and heated to 90 ° C in a stream of nitrogen until no more HCI is produced (approx. 2.5 hours). The slightly yellow colored solution is concentrated and 31 g of a brownish viscous oil are obtained.

Production of the polycarbonate using this chain terminator:

45.7 g of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) (0.2 mol), 16 g of sodium hydroxide (0.4 mol) and 680 ml of distilled water become one Solution. After the addition of 3.87 g of the chain terminator prepared above in 370 nil of methylene chloride, 32 g (0.32 mol) of phosgene are introduced at 20 ° C.- 25 ° C. with stirring. The pH is maintained at pH 12 during the phosgenation by adding 20 ml of 45% aqueous sodium hydroxide solution. After phosgenation has ended, the pH is raised to pH 13-14 by adding a further 20 ml of 45% aqueous sodium hydroxide solution, 4 ml of 4% aqueous triethylamine solution is added and the mixture is stirred for a further 45 minutes. The upper aqueous phase is separated off, the organic phase is acidified and washed free of electrolytes.

The methylene chloride solution is concentrated and the product is dried at 80 ° C. for 12 hours in a vacuum drying cabinet.

The relative solution viscosity is 1.297.

2 h of the polycarbonate obtained are dissolved in 20 ml of methylene chloride, the solutions are placed in a 100 ml round bottom flask and the solvent is removed at 30-40 ° C. in a water jet vacuum on a rotary evaporator.

The flask is immersed in a 300 ° C salt bath for 10 minutes. The relative solution viscosity of the polycarbonate according to the invention thus treated is 1.554.

Claims (8)

1. Process for the production of aromatic polycarbonates having terminal groups containing conjugated double bonds and having average molecular weights Mw (weight average) between 5,000 and 100,000, optionally in admixture with known aromatic polycarbonates having Mw between 5,000 and 100,000, from diphenols, phosgene, 1 to 20 mol %, based on the mols of diphenols, of chain stoppers and optionally branching agents, by the known polycarbonate production methods, namely the phase boundary process or the process in homogeneous solution, characterised in that chain stoppers of the formula (I) X-A-(CH₂)_n-CE=CH-CR=CE-R (I), are used, optionally in combination with at most equal molar amounts of other, known chain stoppers, wherein

R is an aromatic radical with 6 to 20 C atoms or a C₁-C₈-alkyl,

'n" is 0 or an integer between 1 and 7,

X-A- is either X- or

and

X- is a functional group which, in the production of polycarbonates by the two phase boundary process or by the process in the homogeneous phase, acts as the reactive part of the chain stopper of the formula (I).

2. Process according to Claim 1, characterised in that

Xis

wherein

R₁ is an aromatic radical or an aliphatic radical with 1 to 6 C atoms,

-0-Z-0- is a diphenolate radical and

-K- is

3. Aromatic polycarbonates having terminal groups containing conjugated double bonds of the formula (Ia)

wherein

R, 'n" and -A- have the meaning given for formula (1), obtainable according to processes of Claims 1 and 2, optionally in admixture with known aromatic polycarbonates having Mw between 5,000 and 100,000, which result from chain termination using the other known chain stoppers.

4. Polycarbonates having average molecular weights Mw (weight average determined by light- scattering) between 5,000 and 100,000 of the formula (11)

wherein

-0-Z-0- is a diphenolate radical,

E and E' are identical or different and wherein at least one of the radicals E or E' corresponds to

a radical of the formula (Ib)

wherein

R, 'n" and -A- have the meaning given for formula (I) and -Y- is the binding link which results from the reaction of the chain stoppers of the formula (I), optionally including the use of phosgene,

and wherein

the other terminal groups E and E' result from the reaction with the other known chain stoppers, optionally including

and wherein

'p" is the degree of polymerisation which results from the molecular weights Mw of 5,000 to 100,000.

5. Polycarbonates according to Claim 4, characterised in that -Y- is

wherein

R_lis an aromatic radical or an aliphatic radical with 1 to 6 C atoms,

-0-Z-0- is a diphenolate radical and

6. Process according to Claims 1 and 2; characterised in that bifunctional oligomers or polymers having molecular weights Mw (number average) between 500 and 5,000 which are co- condensable under the polycarbonate production conditions are also used in amounts of 0 to 450% by weight, based on the amount by weight of monomeric diphenols used.

. 7. Polycarbonates and polycarbonate mixtures, obtainable according to Claim 6.

8. Mixtures consisting of 5 to 95% by weight of polycarbonate of the formula (II) according to Claims 4 and 5 and 95 to 5% by weight of known aromatic, thermoplastic polycarbonates having Mw (weight average molecular weight) of 10,000 to 200,000.